Saturday, April 17, 2010

Climategate: 'Hockey stick' bashed by statistician

By E. Thomas McClanahan
A report published earlier this week in Britain found that the scientists involved in the Climategate scandal behaved "honestly and fairly," and showed “no evidence of any deliberate scientific malpractice." But the authors of the report weren't so kind to the "hockey stick" graph.
First a word on the "honestly and fairly" business. Apparently the subject of incompetence wasn't covered, but it's germaine given that the scientists involved lost the raw data on which their sweeping conclusions were based, which would explain their desperate efforts to refuse requests for it, which most people thought was normal protocal in the scientific community.
As for the hockey stick graph, Professor David Hand, president of the Royal Statistical Society, said it was compiled using “inappropriate” methods. But Hand added that this didn't invalidate the underlying science, which shows a clear warming trend over time.
The hockey stick came from a study led by U.S. climate scientist Michael Mann, who -- using tree-ring data -- sought to show that over the last 1,000 years temperatures had never been as high as they are now; the hockey stick graph shows readings in recent years shooting up.
Enter Canadian climate skeptic and math whiz Steve McIntyre, who, according to a lengthy piece in the German publication Der Spiegel, programmed his computer using Mann's methodology, and entered random data. The result, said McIntyre, "was a hockey stick curve."
Defenders of anthropogenic global warming desperately maintain, like the authors of the report cited above, that Climategate doesn't invalidate the science.
They miss a critical point. In the public arena, this isn't a debate about science. As Walter Russell Mead points out, it's a debate about policy. Mead's post raking The New York Times for ignoring much of this scandal is a must-read, especially for journalists. An excerpt:
For years now ’skeptic’ has been a dirty word at the Times when the subject of climate change comes up. Excuse me, but reporters are supposed to be skeptics. They are supposed to be cynical, hard bitten people who trust their mothers — but cut the cards. They are supposed to think that scientists are probably too much in love with their data, that issue advocates have hidden agendas, that high-toned rhetoric is often a cover for naked self interest, that bloviating politicians have cynical motives and that heroes, even Nobel Prize laureates, have feet of clay. That is their job; it is why we respect them and why we pay attention to what they write.
Defenders of climate science say pratfalls like the hockey stick, or the recent melting-glaciers blooper, were isolated instances of human error. Maybe. Yet people are entitled to ask, Why have all the errors run in one direction -- toward hype? Read more.

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